Please use the following code snippet:    

 

Sub New()

        InitializeComponent()
        Me.RadTreeView1.Nodes.Clear()
        Me.RadTreeView1.CheckBoxes = True

        Dim node = New RadTreeNode("1") With {.CheckType = CheckType.CheckBox, .Checked = True, .CheckState = ToggleState.Indeterminate}
        RadTreeView1.Nodes.Add(node)
        node.Nodes.Add(New RadTreeNode("1.1") With {.CheckType = CheckType.RadioButton, .Checked = True, .CheckState = ToggleState.Indeterminate})
        node.Nodes.Add(New RadTreeNode("1.2") With {.CheckType = CheckType.RadioButton})
        node.Nodes.Add(New RadTreeNode("1.3") With {.CheckType = CheckType.RadioButton})
        node = New RadTreeNode("2") With {.CheckType = CheckType.CheckBox, .Checked = True, .CheckState = ToggleState.Indeterminate}
        RadTreeView1.Nodes.Add(node)
        RadTreeView1.Nodes.Add(New RadTreeNode("3"))

    End Sub

 

Workaround:

    Sub New()

        InitializeComponent()
        Me.RadTreeView1.Nodes.Clear()
        Me.RadTreeView1.CheckBoxes = True

        Dim node = New RadTreeNode("1") With {.CheckType = CheckType.CheckBox, .Checked = True, .CheckState = ToggleState.Indeterminate}
        RadTreeView1.Nodes.Add(node)
        node.Nodes.Add(New RadTreeNode("1.1") With {.CheckType = CheckType.RadioButton, .Checked = True, .CheckState = ToggleState.Indeterminate})
        node.Nodes.Add(New RadTreeNode("1.2") With {.CheckType = CheckType.RadioButton})
        node.Nodes.Add(New RadTreeNode("1.3") With {.CheckType = CheckType.RadioButton})
        node = New RadTreeNode("2") With {.CheckType = CheckType.CheckBox, .Checked = True, .CheckState = ToggleState.Indeterminate}
        RadTreeView1.Nodes.Add(node)
        RadTreeView1.Nodes.Add(New RadTreeNode("3"))


        Me.RadTreeView1.ExpandAll()
         
    End Sub

    Private Sub RadForm1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Me.RadTreeView1.CollapseAll()

    End Sub